I hate the whole steam having to update/startup/prepare/launch process.
I bought both games as physical copies.
Any sort of a modded .exe that bypasses the steam drm, and instead would allow a GOG install? That would be awesome, considering this game series is not exactly brand new anymore..

What exactly do you mean by "GOG install"?
If you mean "being granted GOG version just because you own physical media" then no - no way.

Other than that, there might be a crack for the game somewhere in the wild (but then again, discussing piracy is against forum rules here, tho it's a grey zone if you use a crack for your legally obtained copies).
But you probably should use Steam emulator (example being Goldberg).
Tho, if you want to bypass DRM in your legally obtained Steam version you should by all means NOT use the files from the disks, as these are RTM version and are very outdated while there's no way to install "standalone patches" or even obtain them from Steam.
Just download the files from Steam normally (ergo install), copy the entire installed directory (default location is in steamapps inside Steam related directories), back it up somewhere safe, then use Goldberg along with it.

Hope that helps ;)